@Override
public Iter iter(final QueryContext ctx) throws QueryException {
final Iter iter = ctx.iter(root);
final Value cv = ctx.value;
final long cs = ctx.size;
final long cp = ctx.pos;
// cache results to support last() function
final ItemCache ic = new ItemCache();
for (Item i; (i = iter.next()) != null; ) ic.add(i);
// evaluate predicates
for (final Expr p : pred) {
final long is = ic.size();
ctx.size = is;
ctx.pos = 1;
int c = 0;
for (int s = 0; s < is; ++s) {
ctx.value = ic.get(s);
if (p.test(ctx, input) != null) ic.set(ic.get(s), c++);
ctx.pos++;
}
ic.size(c);
}
ctx.value = cv;
ctx.size = cs;
ctx.pos = cp;
return ic;
}
